Influence of Carbene and Phosphine Ligands on the Catalytic Activity of Gold Complexes in the Hydroamination and Hydrohydrazination of Alkynes

Through
kinetic measurements, catalytic and stoichiometric experiments,
and DFT calculations, we compare
the catalytic activity of gold complexes supported by a variety of
ligands (R3P, NHC, CAAC-5, CAAC-6, and BiCAAC) in the hydroamination
and hydrohydrazination of alkynes. This study provides a rationale
for the superior efficiency of a gold complex bearing a bicyclic (alkyl)­(amino)
carbene (BiCAAC). We demonstrate that this ligand motif, which is
readily available, provides a durable gold catalyst that is able to
compete with sophisticated state-of-the-art phosphine and NHC ligands,
which feature secondary interaction capabilities.